Bobby Cox posted:Is there a source for purchasing die cast or brass O gage scale box cars? Not kits, painted and ready to roll?
"2-rail" cars (the cars are not 2-rail - cars are "no-rail"; the trucks are the deciding factor) can be equipped with 3-rail trucks. Sometimes the 2-rail trucks can have hi-rail (3-rail) wheel sets inserted; easy or hard, depending. 3RO trucks are readily available on eBay and at train shows here and there. The change can be dead simple to moderately involved, depending on: the truck style/bolster; car design/bolster; removal of frame-mounted coupler pockets and some lower body detail to allow the coupler to swing. Bolsters matter: high/deep truck/car bolsters can have your hopper or whatever showing a silly high-pockets look. I have converted several brass cars to hi-rail.
You mentioned die-cast - all the major brands do/have offered die-cast (not Atlas?) 3RO rolling stock. Look on eBay; usually there are several. I think that K-Line (of course) did more than anybody. The prices are usually average - some people do not like die-cast rolling stock. I do.